Remote service interruption via EDNS0 nil dereference
Published Jul 16, 2026 · Updated Jul 16, 2026
NULL pointer dereference in CoreDNS's rewrite plugin before 1.14.5 allows remote attackers to interrupt DNS service through matching queries. The edns0SetResponseRule and edns0ReplaceResponseRule functions dereference the nil result of IsEdns0 when a downstream response has no OPT record. A rewrite edns0 rule using revert is required; recovery returns SERVFAIL by default, while the debug directive lets the same query crash the process.
Summary
What happened
NULL pointer dereference in CoreDNS's rewrite plugin before 1.14.5 allows remote attackers to interrupt DNS service through matching queries. The edns0SetResponseRule and edns0ReplaceResponseRule functions dereference the nil result of IsEdns0 when a downstream response has no OPT record. A rewrite edns0 rule using revert is required; recovery returns SERVFAIL by default, while the debug directive lets the same query crash the process.
The record
- CVE
- CVE-2026-62299
- Published
- Jul 16, 2026
- Updated
- Jul 16, 2026
- Vendor
- CoreDNS
- Product
- CoreDNS
- Classifications
- CWE-476, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 16, 2026CVE publishedPublication date reported by the CVE source.
- Jul 16, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.14.5
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- CoreDNS EDNS0 response-revert runtime proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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